A digital presenter may be used to display a wide variety of media from printed materials (e.g., transparencies, documents, books, etc.) to other media such as slides, photographs or films, as well as 3-dimensional physical objects.
Unlike analog overhead projectors, a digital presenter may use a digital (still or video) camera to capture images of 2- or 3-dimensional objects that are then conveyed to other output devices (such as television screens or computer monitors) or displayed through an LCD projector, etc.
A digital presenter generally includes a light source(s) capable of providing sufficient illumination to detect and capture images of the media or object to be displayed. In this regard, since the digital presenter relies on a light source(s) for illumination, when an image is captured by the camera, specular reflection (highlight or glare) from the surface of the object to be displayed may adversely affect the quality of the image captured.
In addition, if the surfaces of the materials whose images are being captured are not sufficiently flat, then the captured images may be blurry or out-of-focus. For example, the portions of pages near the spine (or binding) of bound documents (such as books or magazines) tend to be curved, and as a result, such portions may not receive uniform or sufficient illumination, potentially making the images captured from these portions blurry and out-of-focus.
Conventional digital presenters may employ multiple light sources and/or cameras, and strategic positioning of the cameras and/or light sources may be needed for proper functioning—but such systems tend to be cumbersome and costly to implement.